1. Field of the Invention
The invention relates to a discharge mechanism. For example, the invention relates to a discharge mechanism that discharges electric charges accumulated on a smoothing capacitor in the event of a collision of a vehicle, and to the vehicle.
2. Description of the Related Art
A vehicle mounted with a power train called a hybrid system as a combination of an engine (it is assumable to employ a known engine such as a gasoline engine, a diesel engine, or the like) and an electric motor has been developed and put to practical use. In this vehicle, a changeover between operation by the engine and operation by the electric motor is automatically made regardless of an amount by which an accelerator is operated by a driver. Thus, the vehicle is controlled with the highest efficiency.
For example, in the case where the engine is operated in a stationary state to rotate a generator for charging a secondary battery (a battery) or is intermittently operated during running in accordance with a charge amount of the secondary battery or the like, the operation and stoppage of the engine is repeated regardless of the amount by which the accelerator is operated by the driver. That is, an improvement in fuel consumption and a substantial reduction in the emission of exhaust gas can be achieved by operating the engine and the electric motor individually or in cooperation with each other.
In this hybrid vehicle, an electric vehicle, and also a fuel-cell vehicle, a direct-current electric power of the battery is converted into an alternating-current electric power by an inverter, and this electric power is supplied to a three-phase alternating-current motor (a motor generator). Further, during generation of the electric power, in opposition to the flow of this electric power, an alternating electric power generated by the three-phase alternating-current motor (the motor generator) is converted into a direct-current electric power by the inverter to charge the battery. Besides, in the process of this electric power conversion, a voltage may be boosted or lowered. The vehicle may also be equipped with a DC/DC converter to boost/lower the voltage (for the sake of transformation).
Such an electric circuit (an electric power line) is provided with a smoothing capacitor for reducing noise. The smoothing capacitor is pre-charged with a high-voltage electric power, and creates an effect of reducing a rush current flowing into the inverter. In a vehicle (a hybrid vehicle, an electric vehicle, or a fuel-cell vehicle) mounted with this electric circuit (i.e., an electric circuit having a high-voltage storage mechanism), when an accident such as a collision or the like occurs, a baneful influence of high voltage needs to be excluded.
In Japanese Patent Application Publication No. 2006-224772 (JP-A-2006-224772), there is disclosed an art for discharging electric charges accumulated on a smoothing capacitor in the event of a collision of a vehicle using a discharge relay that turns on when the collision occurs.
Further, in Japanese Patent Application Publication No. 2003-189415 (JP-A-2003-189415), there is disclosed an art for moving a fuel cell or a battery accommodation case upon application of an abnormal external force thereto, short-circuiting a positive electrode of the fuel cell to a negative electrode thereof, and thereby consuming accumulated electric energy.
Further, in Japanese Patent Application Publication No. 2001-145202 (JP-A-2001-145202), there is disclosed an art for opening an open port of a conductive member accommodation container, discharging a conductive member into a battery accommodation container, and short-circuiting electrodes of each cell to each other when a short-circuiting request determination unit determines that there is a request for short-circuiting.
However, while electric charges accumulated on the smoothing capacitor in the event of a collision of the vehicle need to be quickly discharged upon the collision, an electric power supply device disclosed in Japanese Patent Application Publication No. 2006-224772 (JP-A-2006-224772) is provided with a circuit that controls the discharge relay to an energized state in accordance with a result of detection of a collision of the vehicle by a controller. Thus, the discharge relay may not be controlled when the controller is damaged. Further, the art disclosed in Japanese Patent Application Publication No. 2003-189415 (JP-A-2003-189415) and the art disclosed in Japanese Patent Application Publication No. 2001-145202 (JP-A-2001-145202) both relate to the batteries. These publications do not disclose any art for discharging electric charges accumulated on a smoothing capacitor.